1. Department of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, P. R. China
2. School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
3. Department of Mechanical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, China
4. Department of Mechanical Engineering, Dongguan University of Technology, Dongguan 523808, P. R. China